A readout system for X-ray powder crystallography

A system for capturing and processing data, from radiation detectors, in the "eld of X-ray crystallographyhas been developed. The system includes a custom-made mixed analog-digital 16-channel VLSI circuit in 50 lm pitch. Each channel comprises a charge ampli"er, a shaper, a comparator and a 21-bit counter. The circuit can be scaled in a daisy chaincon"guration. Data acquisition is performed with a custom made PCI card while the control software is developed with Visual C## under the MS Windows NTenvironment. Performance of a fully operational system, in terms of electronic noise, statistical variations and data capture speed is presented. The noise level permits counting of X-rays down to 8 keV while the counting capability is in excess of 200 kHz. The system is intended for X-ray crystallographywith silicon detectors. ( 2000 Elsevier Science B.V. All rights reserved.